Method for noninvasive measurement of glucose and apparatus for noninvasive measurement of glucose

• US 8,315,681 B2
• Filed: 04/06/2009
• Issued: 11/20/2012
• Est. Priority Date: 11/30/2005
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Inventors: Kanayama, Shoichi, Khalil, Omar S., Jeng, Tzyy-Wen, Yeh, Shu-Jen
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US12/418,899
• Publication Number:
  US 20100016689A1
• Time in Patent Office: 1,324 Days
• Field of Search: 600/310, 600/316, 600/334
• US Class Current: 600/316
• CPC Class Codes: A61B 5/0053 by applying pressure, e.g. compression, indentation, palpation, grasping, gauging
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1491 Heated applicators
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

A method for noninvasive measurement of glucose in a tissue of a subject, including the steps of bringing an adaptation device, which has a shape similar to a measurement probe, into contact with a skin part of a subject for stretching the skin part of the subject under a pressure that is higher than a pressure per unit area applied by the measurement probe during the noninvasive measurement, maintaining the contact for a predetermined period of time followed by relieving the contact, bringing the measurement probe into contact with the stretched skin part of the subject for the noninvasive measurement, collecting signals emitted from the subject, and estimating a glucose concentration based on the collected signals.

Claims

1. A method comprising the steps of:

inducing a change in glucose metabolism in a nutrient capillary in skin by temperature-changed glycolysis;

measuring a change in localized reflectance light signals at a plurality of light source-detector distances and a plurality of wavelengths over a specific time period after skin-probe contact as a function of a time for which a localized reflectance probe is brought into contact with the skin, said temperature-changed glycolysis causing a change with respect to light attenuation, oxygen consumption in a tissue and concentration of a hemoglobin variant;

selecting a time window in which a tissue-probe adaptation effect on the signals is minimized and an effect on glycolysis induced by temperature has time dependence, and using a signal measured in the time window for a subsequent calculation;

calculating one set of functions based on a plurality of localized reflectance values at the plurality of light source-detector distances and the plurality of wavelengths at a plurality of time intervals in the time window and at least two wavelengths;

deriving a calibration relationship between a combination of the calculated functions and a glucose concentration in a living body; and

using the calibration relationship for predicting a glucose concentration in a body fluid in subsequent measurement,

wherein at least one function in the plurality of time intervals is associated with a change in oxygen consumption.

2. The method according to claim 1, wherein the calculating step comprises the step of calculating a rate of change in at least one function associated with the time dependence of a temperature change on the localized reflectance values at the plurality of wavelengths and light source-detector distances over the specific time window.

3. The method according to claim 1, wherein the calculating step comprises the step of calculating a degree of change in at least one function associated with a time dependent effect of temperature stimulation on the localized reflectance values at the plurality of wavelengths and light source-detector distances, and the degree of change is calculated for at least one time window and is averaged over adjacent time windows.

4. The method according to claim 1, wherein the wavelengths have different absorption coefficients with respect to oxyhemoglobin and deoxyhemoglobin.

5. The method according to claim 1, wherein data points used in the calculation are present in a time window which starts after a predetermined time from the skin-probe contact.

6. A noninvasive measurement apparatus comprising:

a unit which modulates a temperature of a localized reflectance optical probe, when the probe has been brought into contact with skin to a temperature substantially different from a normal temperature of the skin for inducing a change in temperature of a tissue in a vicinity of the probe and up to a depth of the skin surrounded by a skin vascular system;

a unit which measures a change in localized reflectance light signals at a plurality of light source-detector distances and a plurality of wavelengths over a specific time period after skin-probe contact as a function of a time for which a localized reflectance probe is brought into contact with the skin;

a unit which selects a time window in which a tissue-probe adaptation effect on the signals is minimized, and uses a signal measured in the time window for a subsequent calculation;

a unit which calculates one set of functions based on a plurality of localized reflectance values at the plurality of light source-detector distances and the plurality of wavelengths at a plurality of time intervals in the time window and at least two wavelengths;

a unit which derives a calibration relationship between a combination of the calculated functions and a glucose concentration in a living body; and

a unit which uses the calibration relationship for predicting a glucose concentration in a body fluid in subsequent measurement,

wherein at least one function in the plurality of time intervals is associated with a change in oxygen consumption.

7. A method, comprising:

inducing a change in glucose metabolism in a nutrient capillary in the skin by temperature-changed glycolysis;

measuring a change in localized reflectance light signals at a plurality of light source-detector distances and a plurality of wavelengths over a specific period of time after skin-probe contact as a function of a time for which a localized reflectance probe is in contact with the skin to determine an oxygen consumption in a tissue and a concentration of a hemoglobin variant with respect to light attenuation;

selecting a time window in the period of time in which a tissue-probe adaptation effect on the localized reflectance light signals is minimized and an effect on the temperature-changed glycolysis has time dependence, and carrying out a subsequent calculation based on a signal measured in the time window;

calculating one set of functions based on a plurality of localized reflectance values at the plurality of light source-detector distances and the plurality of wavelengths at a plurality of time intervals in the time window and at least two wavelengths;

deriving a calibration relationship between a combination of the functions calculated in the step of calculating and a glucose concentration in a living body; and

predicting a glucose concentration in a body fluid based on the calibration relationship;

wherein at least one function in the plurality of time intervals is a change in oxygen consumption.